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Abstract:

A method of inspecting a substrate includes measuring a first current
flowing between a first region and a second region of the substrate using
a first probe. A second current flowing between the first region and the
second region of the substrate may be measured using a second probe
including a material different from that of the first probe. By comparing
the first and second currents, it can be determined whether there is a
change in a physical composition of the substrate and a change in a
physical configuration of the substrate between the first region and the
second region. Thus, when the current change is induced by the change in
a physical configuration of the substrate, a determination error that the
contaminants on the semiconductor substrate may exist based on the
current change may be prevented.

Claims:

1. A method of inspecting a substrate, the method comprising:measuring a
first current flowing between a first region and a second region of the
substrate using a first probe;measuring a second current flowing between
the first region and the second region using a second probe;
anddetermining whether a change in a physical composition of the
substrate and a change in a physical configuration of the substrate exist
between the first region and the second region based on the first current
and the second current.

2. The method of claim 1, wherein the first probe and the second probe are
spaced apart from the substrate by substantially the same distance.

3. The method of claim 1, wherein determining whether the change in a
physical composition of the substrate and the change in a physical
configuration of the substrate exist comprises:deciding that the change
in a physical composition of the substrate and the change in a physical
configuration of the substrate do not exist between the first region and
the second region when the first current and the second current are
zero;deciding that only the change in a physical composition of the
substrate exists between the first region and the second region when the
first current is substantially the same as the second current;
anddeciding that the change in a physical configuration of the substrate
exists between the first region and the second region when the first
current is different from the second current.

4. The method of claim 1, further comprising measuring a third current
flowing between the first region and the second region using a third
probe that is spaced apart from the substrate by a distance greater than
the distance between the first probe and the substrate.

5-15. (canceled)

16. A method of analyzing a substrate, the method comprising:detecting a
first current flowing between a first portion of a substrate and a second
portion of the substrate;detecting a second current flowing between the
first portion of the substrate and the second portion of the substrate;
andcomparing the first current to the second current to determine at
least one of a physical composition of the substrate and a physical
configuration of the substrate.

17. The method according to claim 16, wherein comparing the first current
to the second current comprises:determining whether a first current and a
second current exist; andwhen the first current and the second current
exist, determining whether the first current and the second current are
substantially the same.

18. The method according to claim 16, further comprising:detecting a third
current flowing between the first portion and the second portion of the
substrate,wherein the first current is detected by a first probe
positioned a first distance from the substrate,the second current is
detected by a second probe positioned the first distance from the
substrate, andthe third current is detected by a third probe positioned a
second distance from the substrate, the second distance being greater
than the first distance.

19. The method according to claim 16, wherein detecting the first and
second currents comprises moving first and second probes, respectively,
in a horizontal direction with respect to the substrate across a surface
of the substrate.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims priority under 35 USC §119 to Korean
Patent Application No. 2008-130837, filed on Dec. 22, 2008 in the Korean
Intellectual Property Office (KIPO), the contents of which are herein
incorporated by reference in their entirety.

BACKGROUND

[0002]1. Field of the Invention

[0003]Example embodiments relate to a method of inspecting a substrate and
an apparatus to perform the same. More particularly, example embodiments
relate to a method of inspecting a semiconductor substrate using a
non-contact probe, and an apparatus to perform the method.

[0004]2. Description of the Related Art

[0005]Generally, semiconductor devices may be manufactured by performing a
plurality of processes on a semiconductor substrate. Byproducts generated
after the processes may remain on the semiconductor substrate. The
byproducts may act as contaminants that may negatively affect the
semiconductor substrate. Thus, it may be necessary to perform a process
to detect the contaminants on the semiconductor substrate.

[0006]A probe may be used to detect the contaminants. The probe may be
either a contact probe configured to directly contact the semiconductor
substrate or a non-contact probe configured to not make contact with the
semiconductor substrate. When a contact probe is used, it may damage the
semiconductor substrate. Thus, a non-contact probe may be used to prevent
damage to the substrate. The non-contact probe may be spaced apart from
the semiconductor substrate. The non-contact probe may measure a current
change that flows along a surface of the semiconductor substrate to
detect the contaminants on the semiconductor substrate.

[0007]The current change may be induced by a change in a physical
configuration of the substrate in the configuration, shape, or structure
of the semiconductor substrate as well as by the contaminants. For
example, when a step or a change in a surface level exists between a
first region and a second region of the semiconductor substrate, a
current change measured using the non-contact probe may be generated.

[0008]However, when the current change is measured using the conventional
non-contact probe, it may not be determined whether the current change is
induced by a change in physical composition of the substrate, such as by
the presence of contaminants on or in the substrate, or whether the
current change is induced by a change in the physical features or change
in a physical configuration of the substrate of the substrate.

SUMMARY

[0009]Example embodiments provide a method of inspecting a substrate that
may be accurately discriminate between a current change induced by a
change in the physical composition of a substrate and a current change
induced by a change in a physical configuration of the substrate.

[0010]Example embodiments also provide an apparatus to perform the
above-mentioned method.

[0011]Additional aspects and utilities of the present general inventive
concept will be set forth in part in the description which follows and,
in part, will be obvious from the description, or may be learned by
practice of the general inventive concept.

[0012]Features and/or utilities of the present general inventive concept
may be realized by a method of inspecting a substrate. In the method of
inspecting the substrate, a first current flowing between a first region
and a second region of the substrate may be measured using a first probe.
A second current flowing between the first region and the second region
of the substrate may be measured using a second probe including a
material different from that of the first probe. Whether a change in a
physical composition of the substrate and a change in a physical
configuration of the substrate between the first region and the second
region exist may be determined based on the first current and the second
current.

[0013]Measuring the first current and the second current may include using
the first probe spaced apart from the substrate by a first distance and
the second probe spaced apart from the substrate by a second distance
substantially the same as the first distance.

[0014]Determining whether the change in a physical composition of the
substrate and the change in a physical configuration of the substrate
exists may include deciding that there is neither a change in a physical
composition of the substrate nor a change in a physical configuration of
the substrate when the first current and the second current may be zero,
deciding that only the change in a physical composition of the substrate
exists between the first region and the second region when the first
current is substantially the same as the second current, and deciding
that only a change in a physical configuration of the substrate exists or
that both a change in a physical composition of the substrate and a
change in a physical configuration of the substrate exist between the
first region and the second region when the first current is different
from the second current.

[0015]The method may further include measuring a third current flowing
between the first region and the second region using a third probe spaced
apart from the substrate by a third distance greater than the first
distance.

[0016]Additional features and/or utilities of the present general
inventive concept may be realized by an apparatus to inspect a substrate.
The apparatus to inspect the substrate may include a first probe and a
second probe. The first probe may be located over the substrate to
measure a first current flowing between a first region and a second
region of the substrate. The second probe may be located over the
substrate to measure a second current flowing between the first region
and the second region. The second probe may include a material different
from that of the first probe.

[0017]The first probe may be spaced apart from the substrate by a first
distance and the second probe may be spaced apart from the substrate by a
second distance substantially the same as the first distance.

[0018]The first probe may include stainless steel and the second probe may
include tungsten.

[0019]The apparatus may further include a third probe to measure a third
current that may flow between the first region and the second region. The
third probe may be spaced apart from the substrate by a third distance
greater than the first distance. Further, the third probe may include a
material substantially the same as that of the first probe.

[0020]According to example embodiments, the first current and the second
current flowing between the first region and the second region of the
substrate may be measured using the first probe and the second probe that
may be composed of different materials. Thus, a change in or difference
in the first and second currents may indicate whether the currents are a
result of a difference in a physical composition of the substrate or a
difference in a physical configuration of the substrate. As a result,
when the current change is induced by the change in a physical
configuration of the substrate, a determination error that the
contaminants on the semiconductor substrate may exist based on the
current change may be prevented.

[0021]Features and/or utilities of the present general inventive concept
may also be realized by a substrate testing apparatus including a first
probe positioned a first distance over a substrate to measure a first
current flowing from a first portion of the substrate to a second portion
of the substrate and a second probe positioned a second distance over the
substrate to measure a second current flowing between the first portion
and the second portion of the substrate.

[0022]The first distance is the same as the second distance. The testing
apparatus may further include a third probe positioned a third distance
over the substrate to measure a third current flowing between the first
portion and the second portion, and the third distance may be greater
than the first distance.

[0023]The testing apparatus may further include a comparison unit to
receive outputs from the first probe and the second probe and to
determine whether an output of the first probe is substantially the same
as an output of the second probe.

[0024]The first probe may include a material different than that of the
second probe.

[0025]Features and/or utilities of the present general inventive concept
may also be realized by a method of analyzing a substrate including
detecting a first current flowing between a first portion of a substrate
and a second portion of the substrate, detecting a second current flowing
between the first portion of the substrate and the second portion of the
substrate, and comparing the first current to the second current to
determine at least one of a physical composition of the substrate and a
physical configuration of the substrate.

[0026]Comparing the first current to the second current may include
determining whether a first current and a second current exist and when
the first current and the second current exist, determining whether the
first current and the second current are substantially the same.

[0027]The method may further include detecting a third current flowing
between the first portion and the second portion of the substrate. The
first current may be detected by a first probe positioned a first
distance from the substrate, the second current may be detected by a
second probe positioned the first distance from the substrate, and the
third current may be detected by a third probe positioned a second
distance from the substrate, the second distance being greater than the
first distance.

[0028]Detecting the first and second currents may include moving first and
second probes, respectively, in a horizontal direction with respect to
the substrate across a surface of the substrate.

[0029]Features and/or utilities of the present general inventive concept
may also be realized by a method of analyzing a substrate including
positioning a plurality of current-sensing probes over a first region of
a substrate, such that a first probe is closer to a boundary of the first
region than a second probe, moving the current-sensing probes relative to
the substrate, and detecting a current with each of the current-detecting
probes to determine when a material composition of the first region is
different than a material composition in a second region adjacent to the
first region.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030]The above and/or other aspects of the present general inventive
concept will become apparent and more readily appreciated from the
following description of the exemplary embodiments, taken in conjunction
with the accompanying drawings, in which:

[0031]FIG. 1 is a perspective view illustrating an apparatus for
inspecting a substrate in accordance with some example embodiments;

[0032]FIG. 2 is a perspective view illustrating an apparatus for
inspecting a substrate in accordance with some example embodiments;

[0033]FIG. 3 is a flow chart illustrating a method of inspecting a
substrate using the apparatus in FIG. 1;

[0034]FIG. 4 is a perspective view illustrating a process for inspecting a
substrate having only a change in a physical composition of the
substrate;

[0035]FIG. 5 is a perspective view illustrating a process for inspecting a
substrate having only a change in a physical configuration of the
substrate; and

[0036]FIG. 6 is a block diagram of a substrate test apparatus according to
an embodiment of the present general inventive concept.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037]Reference will now be made in detail to the embodiments of the
present general inventive concept, examples of which are illustrated in
the accompanying drawings, wherein like reference numerals refer to the
like elements throughout. The embodiments are described below in order to
explain the present general inventive concept by referring to the
figures.

[0038]It will be understood that when an element or layer is referred to
as being "on," "connected to" or "coupled to" another element or layer,
it can be directly on, connected or coupled to the other element or layer
or intervening elements or layers may be present. In contrast, when an
element is referred to as being "directly on," "directly connected to" or
"directly coupled to" another element or layer, there are no intervening
elements or layers present. As used herein, the term "and/or" includes
any and all combinations of one or more of the associated listed items.

[0039]It will be understood that, although the terms first, second, third
etc. may be used herein to describe various elements, components,
regions, layers and/or sections, these elements, components, regions,
layers and/or sections should not be limited by these terms. These terms
are only used to distinguish one element, component, region, layer or
section from another region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed a
second element, component, region, layer or section without departing
from the teachings of the present invention.

[0040]Spatially relative terms, such as "beneath," "below," "lower,"
"above," "upper" and the like, may be used herein for ease of description
to describe one element or feature's relationship to another element(s)
or feature(s) as illustrated in the figures. It will be understood that
the spatially relative terms are intended to encompass different
orientations of the device in use or operation in addition to the
orientation depicted in the figures. For example, when the device in the
figures is turned over, elements described as "below" or "beneath" other
elements or features would then be oriented "above" the other elements or
features. Thus, the exemplary term "below" can encompass both an
orientation of above and below. The device may be otherwise oriented
(rotated 90 degrees or at other orientations) and the spatially relative
descriptors used herein interpreted accordingly.

[0041]The terminology used herein is for the purpose of describing
particular example embodiments only and is not intended to be limiting of
the present invention. As used herein, the singular forms "a," "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood that
the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers, steps,
operations, elements, and/or components, but do not preclude the presence
or addition of one or more other features, integers, steps, operations,
elements, components, and/or groups thereof.

[0042]Example embodiments are described herein with reference to
cross-sectional illustrations that are schematic illustrations of
idealized example embodiments (and intermediate structures). As such,
variations from the shapes of the illustrations as a result, for example,
of manufacturing techniques and/or tolerances, are to be expected. Thus,
example embodiments should not be construed as limited to the particular
shapes of regions illustrated herein but are to include deviations in
shapes that result, for example, from manufacturing. For example, an
implanted region illustrated as a rectangle will, typically, have rounded
or curved features and/or a gradient of implant concentration at its
edges rather than a binary change from implanted to non-implanted region.
Likewise, a buried region formed by implantation may result in some
implantation in the region between the buried region and the surface
through which the implantation takes place. Thus, the regions illustrated
in the figures are schematic in nature and their shapes are not intended
to illustrate the actual shape of a region of a device and are not
intended to limit the scope of the present invention.

[0043]Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this invention
belongs. It will be further understood that terms, such as those defined
in commonly used dictionaries, should be interpreted as having a meaning
that is consistent with their meaning in the context of the relevant art
and will not be interpreted in an idealized or overly formal sense unless
expressly so defined herein.

[0044]Hereinafter, example embodiments will be explained in detail with
reference to the accompanying drawings.

[0045]FIG. 1 is a perspective view illustrating an apparatus to inspect a
substrate in accordance with some example embodiments.

[0046]Referring to FIG. 1, an apparatus 100 of this example embodiment may
include a first probe 110 and a second probe 120. The first probe 110 and
the second probe 120 may be connected in parallel with a power supply
140.

[0047]The first probe 110 may be located over a semiconductor substrate S.
In some example embodiments, the first probe 110 may be spaced apart from
an upper surface of the semiconductor substrate S by a first distance D1.
The first probe 110 may include a first material, such as stainless
steel. The first probe 110 may have a cross-sectional area A.

[0048]The first probe 110 may move in a first horizontal direction 101
over the semiconductor substrate S to measure a first current J1 flowing
along the upper surface of the semiconductor substrate S. In some example
embodiments, the semiconductor substrate S may have a first region R1 and
a second region R2. The first probe 110 may be moved from the first
region R1 to the second region R2 to measure the first current J1 flowing
between the first region R1 and the second region R2. The first current
J1 may be obtained from a following formula 1.

[0049]In Formula 1, φR1 represents a work function of the first region
R1, φ1 indicates a work function of the first probe 110,
ε0 represent a vacuum permittivity, ε indicates a
permittivity of a material between the first probe 110 and the
semiconductor substrate S, x represents a step between the first region
R1 and the second region R2, and φR2 indicates a work function of the
second region R2.

[0050]When the step x does not exist between the first region R1 and the
second region R2 and the work function φR1 of the first region R1 is
substantially the same as the work function φR2 of the second region
R2, the first current J1 is zero. That is, when a change in a physical
composition of the substrate and a change in a physical configuration of
the substrate between the first region R1 and the second region R2 do not
exist, the first current J1 does not flow between the first region R1 and
the second region R2.

[0051]In contrast, when a step x exists between the first region R1 and
the second region R2 or the work function φR1 of the first region R1
is different from the work function φR2 of the second region R2, the
first current J1 flows between the first region R1 and the second region
R2. The first probe 110 may measure the first current J1 to determine
whether the change in a physical composition of the substrate or the
change in a physical configuration of the substrate between the first
region R1 and the second region R2 exists.

[0052]The second probe 120 may be arranged over the semiconductor
substrate S. The second probe 120 may be spaced apart from the upper
surface of the semiconductor substrate S by a second distance D2. The
second distance D2 may be substantially the same as the first distance
D1. That is, the first probe 110 and the second probe 120 may be spaced
apart from the upper surface of the semiconductor substrate S by
substantially the same distance. The second probe 120 may include a
second material different from the first material. For example, the
second probe 120 may include tungsten. The second probe 120 may have a
cross-sectional area A substantially the same as that of the first probe
110.

[0053]The second probe 120 may move in a horizontal direction 101
direction over the semiconductor substrate S to measure a second current
J2 flowing along the upper surface of the semiconductor substrate S. The
second probe 120 may measure the second current J2 flowing between the
first region R1 and the second region R2. The second current J2 may be
obtained from a following formula 2.

[0054]In Formula 2, φ2 indicates a work function of the second probe
120.

[0055]When a step or change in physical configuration of the substrate
does not exist between the first region R1 and the second region R2 and
the work function φR1 of the first region R1 is substantially the
same as the work function φR2 of the second region R2, the second
current J2 is zero. That is, when the change in a physical composition of
the substrate and the change in a physical configuration of the substrate
between the first region R1 and the second region R2 does not exist, the
second current J2 does not flow between the first region R1 and the
second region R2.

[0056]In contrast, when a step x or change in physical configuration
exists between the first region R1 and the second region R2 or when the
work function φR1 of the first region R1 is different from the work
function φR2 of the second region R2, the second current J2 may flow
between the first region R1 and the second region R2. The second probe
120 may measure the second current J2 to determine whether the change in
a physical composition of the substrate or the change in a physical
configuration of the substrate between the first region R1 and the second
region R2 exists.

[0057]In Formulas 1 and 2, an identification between the first current J1
and the second current J2 may mean that only the change in a physical
composition of the substrate such as a material change may exist between
the first region R1 and the second region R2 and the change in a physical
configuration of the substrate such as the step x may not exist between
the first region R1 and the second region R2. In contrast, a difference
between the first current J1 and the second current J2 may mean that only
the change in a physical configuration of the substrate may exist between
the first region R1 and the second region R2 or all of the change in a
physical composition of the substrate and the change in a physical
configuration of the substrate may exist between the first region R1 and
the second region R2. That is, the difference between the first current
J1 and the second current J2 may mean that the change in a physical
configuration of the substrate may exist at least between the first
region R1 and the second region R2.

[0058]According to this example embodiment, the currents flowing between
the first region and the second region may be measured using the two
probes including different materials. Thus, whether the current change
may be induced by the change in a physical composition of the substrate
or the change in a physical configuration of the substrate may be
accurately determined.

[0059]FIG. 2 is a perspective view illustrating an apparatus to inspect a
substrate in accordance with some example embodiments.

[0060]Referring to FIG. 2, an apparatus 100a of this example embodiment
may include elements substantially the same as those of the apparatus 100
in FIG. 1 except that the apparatus of this example embodiment may
further include a third probe 130. Thus, the same reference numerals
refer to the same elements and any further descriptions with respect to
the same elements are omitted herein for brevity.

[0061]The third probe 130 may be arranged spaced apart from the upper
surface of the semiconductor substrate S by a third distance D3 (D1+y).
The third probe 130 may include a third material substantially the same
as the first material. The third probe 130 may have a cross-sectional
area A substantially the same as that of the first probe 110.

[0062]The third probe 130 may be moved in the horizontal direction 101
over the semiconductor substrate S to measure a third current J3 flowing
along the upper surface of the semiconductor substrate S. In some example
embodiments, the third probe 130 may measure the third current J3 flowing
between the first region R1 and the second region R2. The third current
J3 may be obtained from a following formula 3.

[0063]In Formula 3, φ3 indicates a work function of the third probe
130, and y represent a height difference between the first probe 110 and
the third probe 130.

[0064]When a step or change in physical configuration of the substrate
does not exist between the first region R1 and the second region R2 and
the work function φR1 of the first region R1 are substantially the
same as the work function φR2 of the second region R2, the third
current J3 is zero. That is, when there is no change in a physical
composition of the substrate and no change in a physical configuration of
the substrate between the first region R1 and the second region R2, the
third current J3 does not flow between the first region R1 and the second
region R2.

[0065]In contrast, when a step x or change in a physical configuration of
the substrate exists between the first region R1 and the second region
R2, or the work function φR1 of the first region R1 is different from
the work function φR2 of the second region R2, the third current J3
may flow between the first region R1 and the second region R2. The third
probe 130 may measure the third current J3 to determine whether a change
in a physical composition of the substrate exists or a change in a
physical configuration of the substrate exists between the first region
R1 and the second region R2.

[0066]In Formulas 1 and 3, when the first current J1 and the third current
J3 are represented as a function having only variables of the work
functions, this may mean that only the change in a physical composition
of the substrate such as a material change exists between the first
region R1 and the second region R2 and the change in a physical
configuration of the substrate such as a step x does not exist between
the first region R1 and the second region R2. In contrast, when the first
current J1 and the third current J3 are represented as a function having
only variables of the height difference y, this may mean that only the
change in a physical configuration of the substrate exists between the
first region R1 and the second region R2 or that both a change in a
physical composition of the substrate and a change in a physical
configuration of the substrate exist between the first region R1 and the
second region R2.

[0067]The change in a physical composition of the substrate and the change
in a physical configuration of the substrate of the semiconductor
substrate S may be clearly discriminated from each other using the first
probe 110 and the second probe 120. Thus, the third probe 130 may be
additionally used in the apparatus 100a.

[0068]FIG. 3 is a flow chart illustrating a method of inspecting a
substrate using the apparatus in FIG. 1.

[0069]Referring to FIGS. 1 and 3, in operation S200, the first probe 110
may measure the first current J1 flowing between the first region R1 and
the second region R2 of the semiconductor substrate S. In some example
embodiments, the first probe 110 may be moved over the semiconductor
substrate S. Alternatively, the semiconductor substrate S may be moved
and the first probe 110 may remain stationary.

[0070]In operation S210, the second probe 120 may measure the second
current J2 flowing between the first region R1 and the second region R2
of the semiconductor substrate S. In some example embodiments, the second
probe 120 may include the second material different from the first
material of the first probe 110. The first probe 110 and the second probe
120 may be separated from the upper surface of the semiconductor
substrate S by substantially the same distance. The first probe 110 and
the second probe 120 may have substantially the same cross-sectional
area.

[0071]In operation S220, it may be determined whether the first current J1
and the second current J2 are zero, and when the first current J1 and the
second current J2 are zero, it may be determined in operation S230 that
there is no change in a physical composition of the substrate and a
physical configuration of the substrate between the first region R1 and
the second region R2.

[0072]In some example embodiments, the zero values of the first current J1
and the second current J2 may mean that the currents are not flowing
through the semiconductor substrate S. Thus, the first region R1 and the
second region R2 of the semiconductor substrate S may include
substantially the same material. Further, there may be no step or change
in physical configuration between the first region R1 and the second
region R2.

[0073]In operation S240, as shown in FIG. 4, it may be determined whether
the first current J1 is substantially the same as the second current J2.
When so, it may be determined in operation S250 that there is a change in
a physical composition of the substrate and that there is no change in a
physical configuration of the substrate between the first region R1 and
the second region R2.

[0074]In some example embodiments, in Formulas 1 and 2, variables may be
the step x and the work functions. Alternatively, the work function
φ1 of the first region R1 and the work function φ2 of the second
region R2 may be constants. Thus, when no step x exists between the first
region R1 and the second region R2, the first current J1 may be
substantially the same as the second current J2. As a result, determining
that a first current J1 and a second current J2 exist and that the first
current J1 and the second current J2 are the same means that there is a
change in a physical composition of the substrate, i.e., a material
change, between the first region R1 and the second region R2.

[0075]In operation S260, as shown in FIG. 5, it may be determined whether
the first current J1 is different from the second current J2. When the
first current J1 is different from the second current J2, it may be
determined in operation S270 that there is a change in a physical
configuration of the substrate and that there may or may not be a change
in a physical composition of the substrate between the first region R1
and the second region R2. Therefore, the difference between the first
current J1 and the second current J2 means that at least a change in a
physical configuration of the substrate exists between the first region
R1 and the second region R2.

[0076]In some example embodiments, in Formulas 1 and 2, because the work
function φ1 of the first region R1 and the work function φ2 of
the second region R2 may be constants, the step x may be the only
variable. Thus, when there is a difference between the first current J1
and the second current J2, it may mean that there is a change in a
physical configuration of the substrate. i.e., that a step exists between
the first region R1 and the second region R2.

[0077]Additionally, whether the current change may be induced by the
change in a physical composition of the substrate or the change in a
physical configuration of the substrate may be accurately determined
using the third probe 130.

[0078]In some example embodiments, the substrate may include the
semiconductor substrate. Alternatively, the method and the apparatuses
may be used for inspecting other substrates such as an LCD substrate.

[0079]FIG. 6 illustrates a block diagram of a substrate analysis or test
apparatus 600 according to an embodiment of the present general inventive
concept. The apparatus 600 may include a mount 610 to hold the substrate
S. A probe unit 620 may be positioned a predetermined distance above the
substrate S to detect a current flowing on the substrate, as disclosed
above. The probe unit 620 may include multiple probes, or there may be
multiple probe units 620. A comparison unit 630 receives an output from
the probe unit 620 to determine whether one or more currents are detected
by the probe unit 620 and whether the one or more currents have a same
magnitude. The comparison unit 630 may output a signal to an external
device, indicating a result of the comparison. For example, when multiple
currents of different levels are detected by the probe unit 620, the
comparison unit 630 may output a signal indicating that a physical
composition of the substrate S changes between a first portion of the
substrate and a second portion of the substrate.

[0080]The apparatus 600 may include a controller to control operation of
the comparison unit 630, the probe unit 620, and or the mount 610. For
example, the controller 640 may control a motor 650 to move the probe
unit 620 relative to the mount 610 and the substrate S in the direction
x. The motor 650 may move either the probe unit 620, the mount 610, or
both. The motor 650 may also move the probe unit 620 and mount 610 in the
vertical direction y relative to each other. The motor 650 may be any
appropriate motor, such as a servo-motor or a step motor. The controller
640 may also control output signals from the comparison unit 630 to
external devices.

[0081]The controller 640 may be a processor, logic, or any combination of
a processor, logic, and memory. The controller 640 may be integral with
the comparison unit 630, or they may be distinct devices or semiconductor
chips. The controller 640 and comparison unit 630 may also be embodied by
computer-readable code stored in memory and executed by a processor.

[0082]According to some example embodiments, the first current and the
second current flowing between the first region and the second region of
the substrate may be measured using the first probe and the second probe
including different materials. Thus, it may be accurately determined
whether a current change of the first current and the second current is
induced by a change in a physical composition of the substrate or by a
change in a physical configuration of the substrate. As a result,
determination errors that contaminants exist on the semiconductor
substrate may be prevented.

[0083]The foregoing is illustrative of example embodiments and is not to
be construed as limiting thereof. Although a few example embodiments have
been described, those skilled in the art will readily appreciate that
many modifications are possible in the example embodiments without
materially departing from the novel teachings and advantages of the
present invention. Accordingly, all such modifications are intended to be
included within the scope of the present invention as defined in the
claims. In the claims, means-plus-function clauses are intended to cover
the structures described herein as performing the recited function and
not only structural equivalents but also equivalent structures.
Therefore, it is to be understood that the foregoing is illustrative of
various example embodiments and is not to be construed as limited to the
specific example embodiments disclosed, and that modifications to the
disclosed example embodiments, as well as other example embodiments, are
intended to be included within the scope of the appended claims.

[0084]Although a few embodiments of the present general inventive concept
have been shown and described, it would be appreciated by those skilled
in the art that changes may be made in these embodiments without
departing from the principles and spirit of the general inventive
concept, the scope of which is defined in the claims and their
equivalents.